JPH02115065A - Roll coater equipment for coating rear of steel strip - Google Patents

Abstract

PURPOSE:To enhance precision of film thickness by providing a magnet roll just before a coater roll for coating the rear of a steel strip and also equipping a magnetic force regulating means. CONSTITUTION:A plurality of electromagnets 8b are provided to the outer cylinder 8a of a magnetic roll 8 and supported by a supporting body 8c. Both the outer cylinder 8a and the electromagnets 8b can be independently turned with each other and the electromagnets 8b can be always held at an optimum angle for a steel strip 1. The distance between the steel strip 1 and the electromagnets 8b can be arbitrarily closed and the action of electromagnetic force can be effectively exerted. The outer cylinder 8a can be rotated while keeping the circumferential velocity thereof at the same velocity as the passing velocity of the steel strip 1 and a flaw due to friction of both is not caused on the steel strip 1. Thereby dispersion of film thickness can be drastically reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention relates to roll coater equipment for coating the back side of a steel strip, which improves the precision of coating film thickness, particularly when coating the back side of a steel strip.

[Prior Art] Colored galvanized iron sheets and the like have conventionally been manufactured by continuously coating steel strips using a roll coater on a continuous coating line. Generally, the front surface is the surface to be inspected.
The back side is called a service coat, so the thickness and appearance of the front side are especially important. Conventional roll coaters used for this purpose include, for example, 7th and 8th roll coaters.
There is something like the one shown in the figure.

FIG. 7 is a schematic layout example of paint baking equipment, where 1 is a steel strip, 2 is a front roll coater, 3 is a backup roll for the front roll coater, 4 is a back roll coater, and 5 is a back roll coater. Lift roll for use, 6 for drying the painted surface,
It is open for printing.

FIG. 8 is an explanatory diagram of the roll coater section in FIG. 7. In the front coater 2, 2a is an applicator roll that rolls into contact with the steel plate surface, and 2b is an applicator roll that rolls into contact with the applicator roll 2a to coat the coating. Pick-up roll that supplies 3
is a backup roll that supports the steel strip 1, and 7 is a paint pan that stores paint. 4 is a back coater, 4a
is an applicator roll, 4b is a pick-up roll, 5
7 is a lift roll that supports the steel strip from the back side, and 7 is a paint pan.

However, in such a roll coater, although the steel strip 1 is supported by the backup roll 3 on the front side,
Since there is no backup roll on the back side, the steel strip 1 is lightly supported by the lift roll 5 and then painted while being pushed up by the applicator roll 4a, so the shape of the strip (warp, bulge, selvage, etc.) Variations in coating film thickness tend to become large due to the influence of catenary fluctuations in the adjustment zone.

On the other hand, with the expansion of the uses of coated steel sheets, the required quality has become more sophisticated, and in particular, in the case of thin film coating, it is required that the coating thickness be uniform on both the front and back surfaces. In response to these demands, for example, Japanese Patent Application Laid-Open No. 57-32755 proposes a method of installing fixed electromagnets before and after a roll coater to draw the steel plate toward the roll coater and then paint the back surface. There is.

[Problem to be solved by the invention]

However, if a plurality of electromagnets are arranged in the width direction of the steel plate in this way, or if a gate-shaped stand with magnets is installed spaced apart in the longitudinal direction of the steel plate, in the actual production line, the adjustment band and the fixed electromagnet cannot be connected. In order to completely prevent product scratches and damage to the electromagnet due to contact with the steel strip, it is necessary to keep the electromagnet far away from the steel strip.If the electromagnet is separated from the steel strip, the effect of electromagnetic force will be significantly weakened, so it is difficult to adjust the distance. Depending on the size and shape of the magnet, the effect of installing an electromagnet may not be obtained.

Furthermore, if the magnetic force of the electromagnet is too strong, it may affect surrounding equipment. In any case, in conventional back coating, the shape of the steel strip, the contact area with the steel strip on the applicator roll due to catenary fluctuations, the force applied to the roll by the steel strip, the force in the longitudinal direction of the steel strip, There was a problem in that the coating film was likely to become unstable across the board width direction, and the coating film thickness varied widely.

This invention has been made in view of these conventional problems, and aims to solve the above problems by, for example, providing a magnetic roll between processes.

[Means to solve the problem]

This invention is a roll coater that applies coating while pushing up the back side of a toning belt with a coater roll, in which a plurality of electromagnets are rotatably arranged inside the roll in the longitudinal direction of the roll, just before the coater roll for back side painting. This is a roll coater equipment for coating the back surface of a steel strip, which is equipped with a magnet roll and means for adjusting the magnetic force of the electromagnet.

[Effect]

Since this invention is configured as described above, the strip is attracted and supported by an electromagnet on the magnetic roll, and after stabilizing the shape of the steel strip, fluctuations in the pass line, etc., the back side is immediately removed. Painted with a roll coater. In other words, the shape of the steel strip stabilized by the magnet roll and the pass line are maintained even on the coater roll, so the contact area of the steel strip on the coater roll and the pressing force are in the width direction of the steel plate.

The coating is made uniform in the longitudinal direction, and variations in coating thickness can be reduced.

〔Example] Hereinafter, the present invention will be explained based on the drawings.

1 to 4 are diagrams showing embodiments of the present invention.

The same parts as in the conventional example are given the same reference numerals.
Eliminate duplicate explanations.

In the figure, 8 is a magnet roll according to the present invention, and FIG. 2 shows its cross section, and FIG. 3 shows its dark blue step surface at the axial position. 8a is the outer cylinder of the magnet roll 8, 8b is a plurality of electromagnets provided inside the outer cylinder, and the support body 8C
Supported by The support body 8c is provided with rotation shafts 8f and 8g at both ends thereof, and is rotatable independently with respect to the outer cylinder 8a via bearings. The rotation shaft 8f also serves as an electromagnet angle adjustment shaft for adjusting the rotation angles of the plurality of electromagnets 8b via the support 8e. 8e is a drive shaft of the magnet roll outer cylinder 8a.

In the above configuration, since the outer cylinder 8a and the electromagnet 8b can rotate independently of each other, the electromagnet 8b can always maintain an optimal angle with respect to the steel strip 1.
This allows the electromagnetic force to be used effectively. Further, since the outer cylinder 8a can rotate at the same peripheral speed as the threading speed of the steel strip 1, the steel strip 1 will not be scratched due to friction between the two.

Further, the support body 8c to which the electromagnet 8b is fixed is connected to the angle adjustment shaft 8.
f, the direction in which the electromagnetic force is applied is adjusted by rotating to the optimum direction according to the dimensions, shape, angle of one winding, etc. of the steel strip. moreover,
An electromagnetic force adjusting device 8d is installed outside of the plurality of electromagnets 8b so that the electromagnetic force of all the electromagnets 8b can be adjusted simultaneously or individually.
Depending on the steel strip size, shape, and coating film measurement results, the electromagnetic force is adjusted either simultaneously or in the length direction of the magnet roll body.

Next, an example of an operation actually carried out by the inventors will be shown.

Example (1) In a continuous coating line, the wet film thickness of water-soluble paint is targeted at 5 μm, and the strip size is 0.7 mm tx.
1600mm, line speed 12mpm.

Reverse coating was performed on the back side under the conditions of an applicator roll peripheral speed of 150 mpm and a pink-up peripheral speed of 40 mpm, and the coating film thickness distribution in the board width direction was measured with and without magnet roll excitation. As a result, as shown in FIG. 5, the effect that the film thickness became uniform in the width direction was observed.

Example (2) In a continuous coating line, the wet film thickness of solvent-based resin paint is targeted at 10 μm, and the strip size is 0.6 mm.
tX 1600mm, line speed 12+npm,
Reverse coating was carried out under the conditions of an applicator roll circumferential speed of 150 mpm and a pick-up circumferential speed of 40 mpm, and comparisons were made in the same manner as in Example (1). As a result, as shown in FIG. 6, a uniform effect in the board width direction is clearly observed.

Example (3) In a continuous coating line, the experiments of Examples (1) and 9 (2) above were conducted using two back coaters as shown in FIG. In the same figure (a), the magnet roll 8 is installed just before the first back roll coater 4A, and in the same figure (■), the magnet roll 8 is installed just before the second back roll coater 4B. , same figure (C), (d)
In this case, a magnetic roll 8 was similarly installed just before the roll coater in the process of coating only the back side, but the same effect as described above was observed for each back coater.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to stabilize the shape of the steel strip and the pass line at the applicator part during backside coating, and it is possible to equalize the contact area and pressing force in the width direction of the plate. Variations in film thickness can be significantly reduced, and therefore, it is extremely effective in improving the accuracy of the film thickness on the back side during double-sided coating.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of the device according to the present invention, FIG. 2 is a side view of the device mainly showing a cross section of the magnet roll according to the present invention, and FIG. 3 is a vertical sectional side view at the axial position of the magnet roll. Figures 4(a) and 4) show examples in which the position of the magnet roll is changed when simultaneously painting the front and back sides of a steel strip.
C) and (d) are schematic diagrams showing each example in which the position of the magnet roll was changed when painting the back side of a steel strip, Figure 5 is a coating thickness distribution diagram when applied with a water-soluble paint, and Figure 6 is a diagram showing the coating thickness distribution when applied with a water-soluble paint. A coating film thickness distribution diagram when using a resin paint, FIG. 7 is a schematic diagram of a conventional roll coater equipment for coating steel strips, and FIG. 8 is an explanatory diagram of the roll coater section in FIG. 7. 1...Torting belt, 4.4A, 4B Old...Roll coater for back side painting, 8...Macnet roll, 8
b... Electromagnet, 8d... Magnetic force adjustment device. Figure 1 Figure 2 Figure 4 (b) Figure 8 Figure 5 Figure 6 Board 160Qmm

Claims (1)

[Claims] (1) In a roll coater that paints the back side of a steel strip while pushing it up with a coater roll, a magnet with multiple electromagnets rotatably arranged inside the roll in the longitudinal direction of the roll is placed just before the coater roll for back side painting. Roll coater equipment for coating the back side of a steel strip, comprising a roll and means for adjusting the magnetic force of the electromagnet.